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    /* 
    1.倘若有一边的值为boolean，那么先将boolean-->number在比较
    2.倘若一边为字符串，一边为number，那么string-->number再比较
     */
    console.log(Number(""));
    console.log(0=="");
    console.log(NaN!=NaN);
    console.log(null===undefined);
    console.log(null==0);
    console.log(Number(null));
    
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